What is the ‘Central Dogma’?

• The central dogma of molecular biology explains the flow of genetic information, from DNA to RNA, to make a functional product, a protein.
• The central dogma suggests that DNA contains the information needed to make all of our proteins, and that RNA is a messenger that carries this information to the ribosomes.
• The ribosomes serve as factories in the cell where the information is ‘translated’ from a code into the functional product.
• The process by which the DNA instructions are converted into the functional product is called gene expression.
• Gene expression has two key stages – transcription and translation.
• In transcription, the information in the DNA of every cell is converted into small, portable RNA messages.
• During translation, these messages travel from where the DNA is in the cell nucleus to the ribosomes where they are ‘read’ to make specific proteins.
• The central dogma states that the pattern of information that occurs most frequently in our cells is:
  • From existing DNA to make new DNA (DNA replication)
  • From DNA to make new RNA (transcription)
  • From RNA to make new proteins (translation).

An illustration showing the flow of information between DNA, RNA and protein.
Image credit: Genome Research Limited

• Reverse transcription is the transfer of information from RNA to make new DNA, this occurs in the case of retroviruses, such as HIV. It is the process by which the genetic information from RNA is assembled into new DNA.

Does the ‘Central Dogma’ always apply?

• With modern research it is becoming clear that some aspects of the central dogma are not entirely accurate.
• Current research is focusing on investigating the function of non-coding RNA.
• Although this does not follow the central dogma it still has a functional role in the cell.